Method and device for coiling thin metal strip, especially hot-rolled or cold-rolled thin steel strip

ABSTRACT

A method for coiling thin metal strip ( 1 ), especially hot-rolled or cold-rolled thin steel strip, on a coiler mandrel ( 3   a ) which is adjusted in diameter. At the beginning, the inner windings ( 12 ) of the coil are coiled on the adjusted coiler mandrel diameter, and, after the final winding of the coil ( 11 ), the coiler mandrel ( 3   a ) is pulled out, or the coil ( 11 ) is taken off. One or more profile grooves ( 17 ) are pressed into one inner winding or into several adjacent inner windings ( 12 ) on the circumference during rotation of the coil.

The invention concerns several methods and several devices for coilingthin metal strip, especially hot-rolled or cold-rolled thin steel strip,on a coiler mandrel, which is adjusted in diameter, in which, at thebeginning, the inner windings of the coil are coiled on the adjustedcoiler mandrel diameter, and, after the final winding of the coil, thecoiler mandrel is pulled out, or the coil is taken off.

Hot-rolled, high-grade thin steel strip is being produced in greater andgreater amounts and is now approaching cold-rolled steel strip in bothquantity and thickness. This is the result of great advances in therolling technology of hot-rolled flat strip. It has become economical toproduce very thin hot-rolled flat products (ultrathin gages) of lessthan 2 mm in greater and greater amounts.

Now that the rolling installations are capable of producing such thinhot-rolled flat products, the machines that follow the rollinginstallations, e.g., the roller table, strip cooling devices, coiler,coil conveyance equipment, and the like, must also be able to meet thenew requirements.

A problem that arises during and after the coiling of thin steel stripis that the inner windings of the coil become detached and collapse onthemselves. Subsequent winding of the coil onto a coiler mandrel of theuncoiling machine or of another machine for further processing is notpossible or is possible only with additional labor and expense. Theinner windings of the coil must be cut from the eye of the coil by hand.This manual work reduces the productivity of the plant.

U.S. Pat. No. 5,705,782 describes a spot welding device, which isarranged on a guided support assembly and can be inserted into the eyeof the coil to place the weld spots on the inner winding of the coil byelectrodes.

In Patent Abstracts of Japan, Vol. 014, No. 478 (M-1036) of Oct. 8,1990, a method is described in which the steel strip is bonded with adouble-sided adhesive tape with the continuous use of a tape-likeprocess material and a special coiling device with a pressing roll tocoil the steel strip together with the adhesive tape on a reel.Moreover, no expandable coiler mandrel is provided. Although this makesit possible to prevent the collapse of the inner windings at thebeginning of the coiling process, the method is uneconomical in light ofthe double-sided adhesive tape that is continuously required. Inaddition, a considerably greater length of steel strip must later beregarded as scrap.

JP 50[1975]-113 456 A, published on Sep. 5, 1975, describes anotherwell-known method. There is no provision for a coiler mandrel with anadjustable diameter. The method involves the use of a punching machinefor punching holes by making free punches of flap pieces, such that ineach case in a row an upper flap of an outer winding is to be pressedagainst the next more inner flap of the innermost winding of the eye ofthe coil. An expandable coiler mandrel could be damaged by theprojections that are formed. Here again, collapse of the inner windingsof a coil is prevented, but it would be necessary to avoid damage to anexpandable coiler mandrel that might be inserted.

The problem of the collapse of the inner winding arises with decreasingstrip thickness. Other parameters that have an effect are, for example,material properties, coiler temperature, and strip width. The metalstrip no longer has sufficient inherent rigidity and falls into theinside opening of the coil (coil eye) under its own weight and thusreduces the inside diameter of the coil. The problem developsimmediately after the coiling of the coil and its removal from thecoiler mandrel and intensifies as the coil is further conveyed, untilseveral inner windings have become separated. The aforementioned spotwelding method or fastening by welding or by winding on a sleeve is usedin the cold rolling and coiling of thin steel strip.

The objective of the invention is to prevent the separation ofindividual windings in the eye of the coil by stiffening the windings.

The stated objective is achieved by a first method in accordance withthe invention, in which one or more profile ridges or profile groovesare pressed into one inner winding or into several adjacent innerwindings on the circumference during rotation of the coil.

This measure results in stiffening of the first two windings in such away that the end of the strip is able to support itself again, andindividual windings cannot become separated. In this regard, it issufficient to profile only slightly more than one inner winding. In nocase is it necessary to profile more than 2-3 windings.

It is advantageous to press the profile ridges or profile grooves bymeans of the profiled, rotationally driven coiler mandrel.

In addition, the profiles can be pressed during the coiling of the metalstrip.

Another embodiment is characterized by the fact that, after the coilingof the first winding on the coiler mandrel, a re-expansion is carriedout, and the profiles are pressed into the inner windings with a forcethat depends on the strip and the material. In this way, neither thepreceding operational sequence nor the design of the coiler mandrel areappreciably altered.

The method can be advantageously applied to strip gages on the order of0.4 to 1.8 mm.

The associated device for coiling thin metal strip, especiallyhot-rolled or cold-rolled thin steel strip, with a drivable coilermandrel, which can be adjusted in diameter by means of expandablesegments and can be adjusted to a coil inside diameter and to a diameterfor detaching the finished coil, achieves the stated objective of theinvention by virtue of the fact that the segments are provided withsegmental profile ridges. These profile ridges are pressed into themetal strip by the coiler mandrel forward slip or a re-expansionoperation and form grooves in it, which leads similarly to a stiffeningof the grooved inner windings. The profile ridges are designed accordingto the required plastic deformation of the metal strip and must nothinder the removal of the coil from the coiler mandrel. In this way, noadditional machine is needed, but rather merely one more function istransferred to the coiler mandrel. The pressing of grooves causes nodamage to the strip edges, as occurs by welding or binding. Existingplants can be easily retrofitted. Downstream installations require nomodifications.

In a modification of this device, it is provided that the segmentalprofile ridges are interchangeable and can be adapted in height andwidth to the metal strip.

The width and height of the profile ridges can also be advantageouslyestablished as a function of the strip gage and the material properties.

In accordance with the invention, a second method for achieving theobjective of the invention is characterized by the fact that the innerwindings of the coil are mechanically supported along the circumferenceduring or immediately after the removal of the coil from the coilermandrel in the eye of the coil. This also prevents the inner windingsfrom collapsing.

The inner windings are held against the adjacent middle windings by theinner windings being supported by radial expansion of support elementsaway from the central axis.

In accordance with a modification; it is provided that the supporting ofthe inner windings overlaps the removal of the coil from the coilermandrel.

Further advantages are derived from the fact that the support elementsare kept in their supporting position during the coil conveyance and thecooling phase and up to the uncoiling of the coil.

The associated device for coiling thin-metal strip, especiallyhot-rolled or cold-rolled thin steel strip, with a drivable coilermandrel, which can be adjusted in diameter by means of expandablesegments and can be adjusted to a coil inside diameter and to a diameterfor detaching the finished coil, achieves the stated objective of theinvention by virtue of the fact that an expansion adapter is provided,which can be inserted into the open eye of the coil and is mounted on aholder with a guide. After the coiling of the coil, the mandrel stepbearing opens, and the coil sled conveys the coil out of the coiler andpushes it by the device with the expansion adapter into a standbyposition. The device with the expansion adapter then turns the loosewindings back in the opposite coiling direction until the windings restagainst each other again. To this end, the expansion adapter expandsduring the turning operation. The expansion adapter then presses againstthe inner windings without damaging them, and a disconnection from theholder and the expansion adapter is carried out. The expansion adapterremains in the coil and is removed only later at a downstream station.Collapsing of the inner windings is thus prevented. The turning back andfixation can also occur during the conveyance of the coil away from thecoiler mandrel, which saves time.

In accordance with a modification, it is advantageous with respect tothe necessary movements to provide the expansion adapter withconnections for media, power, and control mechanisms.

In accordance with a refinement, the expansion adapter is rotatablysupported in the holder. In accordance with the above description, theexpansion adapter can be fixed in place in the eye of the coil withouttriggering the turning back of the loose windings. The device with theexpansion adapter can thus be realized optionally with or without aturning mechanism.

In accordance with another handling method, the expansion adapter can beremoved at a downstream station for treatment of the coil.

Additional features of the expansion device derive from the fact thatthe expansion adapter has several support elements distributed along thecircumference it is also possible to provide a simple mechanism fordisconnecting the expansion adapter from the holder or locking it.

Another feature of the expansion adapter is that it can be mechanicallylocked in the operating position in the eye of the coil.

Another advantage is that the expansion adapter can be mass-produced andcan be assigned to each coil. The expansion adapter can be removed fromthe coil at the following station. It can be removed manually or bymachine and then returned for reuse. The expansion adapter isconstructed in a simple, light, and easily handled design, so that massproduction is economical for equipping a large number of coils. Thesystem with expansion adapters likewise avoids damage to the edges ofthe strip by welding. Retrofitting in existing plants is possible.

In a variant of this method, the rotationally driven coiler mandrelserves as the holder for the expansion adapter.

In accordance with the invention, a third method for achieving theobjective of the invention is characterized by the fact that at leastthe first inner winding is joined over a large area with the secondinner winding by introducing adhesives, fillers, pieces of metal,bonding agents, or the like into an angular space between the in netwindings. This holds the first and second inner windings together, whichalso produces stiffening of the inner windings.

In a modification of this type of joining or joint system, it isprovided that the adhesive is sprayed into the angular space between thefirst and second inner windings.

In another variant, a wire-like body is played into the angular spacebetween the first and second inner windings as a filler to producepositive interlocking.

In a third variant, individual metal bodies are introduced into theangular space between the first and second inner windings to producepositive interlocking.

Finally, in a fourth variant, a bonding agent is applied in the angularspace between the first and second inner windings.

The associated device for coiling thin metal strip, especiallyhot-rolled or cold-rolled thin steel strip, with a drivable coilermandrel, which can be adjusted in diameter by, means of expandablesegments and can be adjusted to a coil inside diameter and to a diameterfor detaching the finished coil, achieves the stated objective of theinvention by virtue of the fact that a spreading, spraying, or injectingdevice is provided, which is connected to a reservoir for adhesives,fillers, metal bodies, bonding agents, or the like. Accordingly, nocomplicated machines are necessary to achieve the desired effect, butrather only a simple device for supplying materials or bodies is needed.When adhesives or bonding agents are introduced, only a short amount oftime is required to join the two inner windings. In addition, damage tothe strip edges by welding is again eliminated. Existing plants can beeasily retrofitted with the device. No alterations are required atsubsequent treatment stations. The joint that has been created pullsapart by itself at subsequent processing stations.

Additional advantages derive from the fact that the spreading, spraying,or injecting device can be precisely actuated with respect to time by acomputer-controlled control system.

The device can be refined by providing the spraying or injecting devicewith a nozzle for the systematic introduction of adhesive or bondingagent.

In accordance with the invention, a fourth method for achieving theobjective of the invention is characterized by the fact that, if thecoil is being wound in the clockwise direction, the leading end of thestrip is positioned in the eye of the coil in an angular sector withinthe 7-10 o'clock range, and if the coil is being wound in thecounterclockwise direction, the leading end of the strip is positionedin the eye of the coil in an angular sector within the 2-5 o'clockrange, and then the coil is taken off the coiler mandrel. The weightF_(G) of the end of the strip forces (normal force F_(N)) the end of thestrip to be pressed against the next inner winding, thereby preventingcollapse of the winding, and, in addition, produces the frictional forceF_(R), which prevents the inner winding from separating from the secondinner winding or sliding on the second inner winding.

In this regard, it is also advantageous for the trailing end of thestrip to be positioned in an angular region below 270°.

In a modifying step, the position of the given leading end of the stripis determined by integrating the peripheral speed of one of two driverolls of the coiler or the mean value of the drive roll peripheralspeeds. In this way, only control-engineering measures within the drivecontrol system and its programs are necessary, so that the expense isfurther reduced.

Another refinement provides that the position of the leading end of thestrip is determined by integrating a speed signal from a speed-measuringdevice between a piece of rolling equipment and the coiler.

Another measure for determining the position of the trailing end of thestrip and/or the leading end of the strip consists in comparing thesurface speeds of the coiler mandrel and the inner surface of the coil.When there is agreement within a preset range of error, the position ofthe leading end of the strip on the coiler mandrel is stored, and thenthe position of the mandrel is monitored in the further course ofcoiling.

The designated surface speed can be determined, for example, in such away that the surface speed of the inner surface of the coil isdetermined from the speed signal used for the integration and from aninstantaneous outer diameter and instantaneous inner diameter of thecoil being formed.

Other aids involve determining apposition of the coiler mandrel byevaluating a fixed pulse from a speed sensor located on the coilermandrel or mandrel drive and integrating the speed of the coiler mandreldrive between two pulses.

In another measurement step for determining the trailing end and leadingend of the strip, after the position of the leading end of the strip hasbeen stored, the peripheral speeds of the coiler mandrel and the innersurface of the coil are repeatedly compared, and, when deviations aredetected, the actual effective diameter of the drive rolls of the coileris corrected.

Embodiments of the invention are illustrated in the drawings andexplained in greater detail below.

FIG. 1 shows a side view of a complete coiler with a conveyance rollertable.

FIG. 2 shows a perspective view of a finished coil.

FIG. 3 shows a perspective view through the coil along with the detail“A” of an enlarged inner winding.

FIG. 4 shows a perspective view of a coiler mandrel.

FIG. 5 shows a perspective cutaway view of a coil with an expansionadapter inserted.

FIG. 6 shows the first inner winding of a coil that is being coiled on acoiler mandrel.

FIG. 7 shows a perspective view of a coil, whose strip trailing end andstrip leading end are positioned by control measures.

FIG. 8 shows a signal-flow diagram for the positioning of the leadingend of the strip.

In accordance with FIG. 1, thin metal strip 1, especially thin steelstrip, on a roller table 2 is coiled on a coiler mandrel 3 a in acoiling station 3, in which the metal strip 1 is shaped and coiled bydeflecting rolls 7 via a pair of drive rolls 4 and guides 5 and 6. Inthis regard, the deflecting rolls 7 and pressing rolls 8 can be adjustedby a control system with adjusting cylinders 9, which have positionsensors 10.

This coiling operation produces a coil 11, as shown in FIG. 2. In thecoiling station 3, which, for example, follows a hot-rolled wide striprolling train, the coil 11 is formed on the coiler mandrel 3 a in such away that the (hot) metal strip 1 entering the station at rolling speedis wound around the coiler mandrel 3 a via the pressing rolls 8 and thedeflecting rolls 7, and the metal strip 1 is guided around hydraulicallyby means of the adjusting cylinder 9 and the position sensor 10, so thata first inner winding 12 with a strip leading end 13 is formed. Thediameter of the coiler mandrel 3 a can usually be adjusted by fourmovable segments 3 b mounted around the circumference of the coilermandrel 3 a.

The coiler mandrel has a maximum and a minimum diameter, which is presetwith mechanical stops. The coiling phase starts with an intermediatediameter, i.e., from this position of the segments 3 b, it is possible,for one thing, to expand for the purpose of a rapid buildup of thefrictional connection between the coiler mandrel 3 b and the metal strip1, and, for another, to contract the coiler mandrel 3 a to allow theremoval of the coil 11 from the coiler mandrel 3 a.

In the initial coiling phase, the pressing rolls 8 and the coilermandrel 3 a rotate at a higher speed (so-called forward slip) than thestrip 1 that is running in. The first inner winding 12 is laid aroundthe pre-expanded coiler mandrel 3 a and begins to tighten on the coilermandrel 3 a. The first inner winding 12 shows a tendency for its stripleading edge 13 to fall in below the inside diameter 14 of the eye 15 ofthe coil.

This collapse of the leading edge of the strip must be eliminated. Inaccordance with a first method, the following procedure is followed: There-expansion phase starts, and the segments 3 b are pressed into thefirst inner winding 12 with a force that depends on the metal strip 1and the material from which it is made.

For this purpose, profile ridges (16), which form segmentally peripheralelevations, are mounted on the segments 3 b of the coiler mandrel 3 a(FIGS. 3 and 4). With the forward slip or the re-expansion operation,the profile ridges 16 press profile grooves 17 (FIG. 3) into the metalstrip 1. In this regard, a profile groove 17 can be pressed into themetal strip as far as the second inner winding 18, as shown in theenlarged detail A of FIG. 3. As a result, the inner windings 12 and 18together behave more stiffly and prevent the tendency to collapse thatis shown in FIG. 2.

The segmental profile ridges 17 can be designed to be interchangeableand may vary in width and height, i.e., they can be adapted to the givenmetal strip 1. The adaptation depends not only on the strip gage, butalso on the material properties of the metal strip 1.

In accordance with a second method (FIG. 5), the inner windings 12, 18are mechanically supported along the circumference during or immediatelyafter the removal of the coil 11 from the coiler mandrel 3 a in the eye15 of the coil. The inner windings 12 and 18 are supported by radialexpansion of support elements 19 away from the central axis.

The supporting of the inner windings 12 and 18 may overlap the removalof the coil 11 from the coiler mandrel 3 a. The support elements 19 maybe kept in the supporting position shown in the drawing during the coilconveyance and the cooling phase of the (hot) metal strip 1 up to theuncoiling of the coil 11.

The support elements 19 are part of an expansion adapter 20 inserted inthe open eye 15 of the coil. The expansion adapter 20 is mounted on aholder (not shown) with a guide 21. The expansion adapter 20 is providedwith connections 22 for media, power, and control mechanisms. Theexpansion adapter 20 can be rotated, as indicated by the arrows 23, anddoes not need to be removed until it reaches a subsequent station fortreatment of the coil 11. The support elements 19 can be provided in oneor more radial planes of the expansion adapter 20.

In the operating position 24 shown in FIG. 5, the expansion adapter 20can be locked in place in the eye 15 of the coil. The expansion adapter20 is mass-produced and is assigned to each coil 11. The rotationallydriven coiler mandrel 3 a may also serve as the holder for the expansionadapter 20.

In a third method (FIG. 6), at least the first inner winding 12 and thesecond inner winding 18 are joined over a large area by introducingadhesives, fillers, metal bodies, and/or bonding agents 25 or the likeinto an angular space 26 between the inner windings 12 and 18. Theadhesive is preferably sprayed into the angular space 26 between thefirst and second inner windings 12, 18. Similarly, a wire-like body canbe introduced into the angular space 26 between the first inner winding12 and second inner winding 18 as a filler to produce positiveinterlocking. Similarly, individual metal bodies can be introduced intothe angular space 26 to produce the positive interlocking. It is alsopossible to introduce a bonding agent into the angular space 26 betweenthe inner windings 12 and 18. The steps of the method described abovecan be carried out by means of a spreading, spraying, or injectingdevice 27 connected to a reservoir 28.

A fourth method (FIG. 7) provides that, if the coil 11 is being wound inthe clockwise direction, the leading end 13 of the strip is positionedin the eye 15 of the coil in an angular sector within the 7-10 o'clockrange, and if the coil 11 is being wound in the counterclockwisedirection, the leading end 13 of the strip is positioned in the eye 15of the coil in an angular sector within the 2-5 o'clock range, and thenthe coil 11 is taken off the coiler mandrel 3 a, the end of the strip tobe positioned in an angular region below 270°.

The position of the given leading end of the strip is determined fromthe coil outside diameter 30, a speed sensor and correction values viathe drive rolls 8 or the mean value of the drive roll peripheral speeds,via a speed signal from a speed measuring device, or via the surfacespeeds of the coiler mandrel 3 a and the inner surface of the coil.

The weight F_(G) (in the enlarged detail drawing B) of the leading end13 of the strip forces (by normal force F_(N)) the leading end 13 of thestrip to be pressed against the next inner winding, thereby preventingcollapse of the winding, and, in addition, produces the frictional forceF_(R), which prevents the first inner winding 12 from separating fromthe second inner winding 18 or sliding on the second inner winding 18.

FIG. 8 shows a suitable signal-flow diagram for the positioning of theleading end 13 of the strip. The metal strip 1 is driven by the lowerdrive roll motor 31 and the upper drive roll motor 32, and a coilermandrel motor 33 drives the coiler mandrel 3 a. The position of theleading end 13 of the strip is determined by storage and integration ofa speed signal from a speed measuring device 34 between a piece ofrolling equipment and the coiling station 3 in speed n1. The surfacespeed of the inner surface of the coil 11 is determined from the speedsignal used for the integration and from an instantaneous outer diameterand instantaneous inner diameter of the coil 11 being formed. To thisend, the degree of mandrel expansion is. determined from the speeds ofthe coil 11 and of the coiler mandrel 3 a (V_(mandrel)) and as afunction of the coiler mandrel diameter d_(mandrel). The degree ofmandrel expansion n2 is measured from the leading end 13 of the strip, acoiler mandrel position measuring unit 35, and a coiler mandrel speedmeasuring unit 36. From the coiler mandrel position measuring unit 35and the coiler mandrel speed measuring unit 36, the coiler mandrel motor33 is calculated via a coiler mandrel current regulator 37.

List of Reference Numbers

1 metal strip

2 roller table

3 coiling station

3 a coiler mandrel

3 b segment

4 pair of drive rolls

5 guide

6 guide

7 deflecting roll

8 pressing roll

9 adjusting cylinder

10 position sensor

11 coil

12 first inner winding

13 leading end of the strip

14 inside diameter

15 eye of the coil

16 profile ridges

17 profile groove

18 second inner winding

19 support elements

20 expansion adapter

21 guide

22 connections

23 arrows for rotation

24 operating position

25 adhesive, filler, etc.

26 angular space

27 spreading, spraying, injecting device

28 reservoir

29 trailing end of the strip

30 outside diameter of the coil

31 lower drive roll motor

32 upper drive roll motor

33 coiler mandrel motor

34 speed measuring device

35 coiler mandrel position measuring unit

36 coiler mandrel speed measuring unit

37 coiler mandrel current regulator

n1 speed

n2 degree of mandrel expansion

1.-8. (canceled)
 9. Method for coiling thin metal strip, especiallyhot-rolled or cold-rolled thin steel strip (1), on a coiler mandrel (3a), which is adjusted in diameter, in which, at the beginning, the innerwindings (12, 18) of the coil are coiled on the adjusted coiler mandreldiameter, and, after the final winding of the coil (11), the coilermandrel (3 a) is pulled out, or the coil (11) is taken off, wherein theinner windings (11, 12) of the coil (11) are mechanically supportedalong the circumference during or immediately after the removal of thecoil (11) from the coiler mandrel (3 a) in the eye (15) of the coil. 10.Method in accordance with claim 9, wherein the inner windings (11, 12)are supported by radial expansion of support elements (19) away from acentral axis.
 11. Method in accordance with claim 9, wherein thesupporting of the inner windings (11, 12) overlaps the removal of thecoil (11) from the coiler mandrel (3 a).
 12. Method in accordance withclaim 9, wherein the support elements (19) are kept in their supportingposition during the coil conveyance and cooling phase, and up to theuncoiling of the coil (11). 13.-36. (canceled)